U.S. patent application number 11/213384 was filed with the patent office on 2006-08-31 for embossing plate with a three-dimensional structure for the production of documents by a hot-cold laminating press.
Invention is credited to Erik Mitterhofer, Markus Prancz, Maximilian Reissig.
Application Number | 20060191861 11/213384 |
Document ID | / |
Family ID | 35429233 |
Filed Date | 2006-08-31 |
United States Patent
Application |
20060191861 |
Kind Code |
A1 |
Mitterhofer; Erik ; et
al. |
August 31, 2006 |
Embossing plate with a three-dimensional structure for the
production of documents by a hot-cold laminating press
Abstract
The invention concerns an embossing plate for a
hot-cold-laminating press with a three-dimensional structure based
on an essentially flawless metal plate with a hardened surface of
appropriate thickness and dimensions and a suitable surface,
specifically a highly polished surface, into which or onto which
the three-dimensional structure is incorporated by a process with
at least two steps. An embossing plate produced by this process is
used for the production of documents, specifically security
documents, such as personal identity cards, passports,
identification cards, credit cards, customer cards, driving
licenses and similar sheet and/or card and/or book-like documents
by means of hot-cold-lamination and/or embossing and/or
item-by-item embossing.
Inventors: |
Mitterhofer; Erik; (Wien,
AT) ; Prancz; Markus; (Wien, AT) ; Reissig;
Maximilian; (Perchtholdsdorf, AT) |
Correspondence
Address: |
BAKER & DANIELS LLP;111 E. WAYNE STREET
SUITE 800
FORT WAYNE
IN
46802
US
|
Family ID: |
35429233 |
Appl. No.: |
11/213384 |
Filed: |
August 26, 2005 |
Current U.S.
Class: |
216/2 |
Current CPC
Class: |
B44C 1/228 20130101;
B42D 25/425 20141001; B44C 1/227 20130101; B42D 25/328 20141001;
B44C 1/225 20130101; B42D 25/00 20141001; B42D 25/24 20141001; B44B
5/026 20130101; B42D 25/324 20141001; B42D 2035/26 20130101; Y10S
72/70 20130101; B42D 25/23 20141001 |
Class at
Publication: |
216/002 |
International
Class: |
C23F 1/00 20060101
C23F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 27, 2004 |
DE |
10 2004 041 434.3 |
Claims
1. A process to produce an embossing plate (1) for a
hot-cold-laminating press with three-dimensional structures to
prepare documents (28) by means of lamination and/or surface
embossing characterized by the production of recessed (3, 7, 8, 9,
13, 14, 15, 16) and raised structures (4, 5, 10, 11, 17) relative
to a highly polished surface (6) defined as the reference
level.
2. The process according to claim 1, characterized by having
recessed structures produced in a single-step structuring process
without damage of the uninvolved embossing plate surface (6).
3. The process according to claim 1 or 2, characterized by having
raised structures produced in a single-step structuring process
without damage of the uninvolved embossing plate surface (6).
4. The process according to at least one of claims 1 to 3,
characterized by having recessed and/or raised structures produced
in at least a two-step structuring process with the first process
step producing recessed and/or raised structures in the
unstructured embossing plate surface (6) and with the at least
second step producing additional recessed and/or raised structures
in the unstructured surface (6) and/or in the previously structured
surface and where at least one of the recessed and/or raised
structures of the first or the at least second step has an
optically responsive structure.
5. The process according to one of claims 1 to 4, characterized by
having the surface (6) embodied as highly polished or satin or
matt.
6. The process according to one of claims 1 to 5, characterized by
having the recessed (3, 7, 8, 9, 13, 14, 15, 16) and raised
structures (4, 5, 10, 11, 17) with circular, parabolic,
rectangular, V-shaped, trapezoid and/or composite shapes.
7. The process according to one of claims 1 to 6, characterized by
having the recessed (3, 7, 8, 9, 13, 14, 15, 16) and raised
structures (4, 5, 10, 11, 17) produced by a chemical and/or
galvanic and/or laser-ablative and/or laser deposition process.
8. The process according to one of claims 1 to 7, characterized by
having the recessed (3, 7, 8, 9, 13, 14, 15, 16) and raised
structures (4, 5, 10, 11, 17) produced with at least one photo
masking process.
9. The process according to one of claims 1 to 8, characterized by
having at least one recessed (3, 7, 8, 9, 13, 14, 15, 16) or one
raised structure (4, 5, 10, 11, 17) with a lens shape.
10. The process according to one of claims 1 to 9, characterized by
having the lens shaped structure (3, 7, 8, 9, 19, 20, 21, 23, 24,
25, 26, 27) produced by undercut.
11. The process according to one of claims 1 to 10, characterized
by having the recesses (13, 14, 15, 22) produced by chemical
ablation, where the form of the margins is controlled by
corresponding control of the undercut process.
12. The process according to one of claims 1 to 11, characterized
by having the lens shaped structure (3, 7, 8, 9, 19, 20, 21, 23,
24, 25, 26, 27) embodied as a recessed (3, 7, 8, 9, 19, 20, 21) or
raised (23, 24, 25, 26, 27) structure.
13. The process according to one of claims 1 to 12, characterized
by having the lens shaped structure (3, 7, 8, 9, 19, 20, 21, 23,
24, 25, 26, 27) embodied as a raster or line, where the raster
separation (7, 15, 20) is adjusted to 100 to 300 .mu.m and the
depth (9, 14, 21) or height (10, 11) of the structures is adjusted
between 2 and 150 .mu.m, specifically 5 to 100 .mu.m.
14. The process according to one of claims 1 to 13, characterized
by having the embossing plate (2) embodied as a non-pitted or
generally flawless stainless steel plate or a steel plate with the
appropriate galvanic nickel surface or a galvanically produced
nickel plate, where the surface is highly polished or has the
desired matt surface, and where this surface is modified only in
the areas where a structure is to be added.
15. The process according to one of claims 1 to 14, characterized
by having the embossing plate (2) embodied as a galvanized plate
with a previously produced first structure (3, 7, 8, 9, 19, 20, 21,
23, 24, 25, 26, 27) for the production of additional
structures.
16. The process according to one of claims 1 to 15, characterized
by having a diffractive structure (35) situated on the raised
structure (26).
17. The process according to one of claims 1 to 16, characterized
by having the embossing plate for a hot-cold-laminating press with
three-dimensional structures on both sides of a highly-polished
embossing plate surface (6).
18. The process according to one of claims 1 to 17, characterized
by using an embossing plate (1) for a hot-cold-laminating press
with a three-dimensional structure to produce documents (28),
specifically security documents, such as personal identity cards,
passports, identification cards, credit cards, customer cards,
driving licenses and similar sheet and/or card and/or book-like
documents by means of lamination and/or embossing and/or
item-by-item embossing.
19. An embossing plate (I) according to one of claims 16 or 17,
characterized by being produced in accordance with one of process
claims 1 to 14.
20. Use of an embossing plate (1) produced by one of claims 1 to 14
in a hot-cold-laminating press, specifically a transfer press in
the form of a single cycle press, a layer press or a round table
and similar laminating system or in a full-area and/or individual
embossing press with appropriate thermal and/or printing and/or
ultrasound and/or microwave support to produce documents (28),
specifically security documents.
21. Process to produce laminated cards or identification cards and
similar documents by use of an embossing plate that is produced in
accordance with one of claims 1 to 18.
Description
[0001] The object of the invention is an embossing plate for a
hot-cold-laminating press with a three-dimensional structure, the
production of such an embossing plate, and the application in the
production of documents, specifically security documents, such as
personal identity cards, passports, identification cards, credit
cards, customer cards, driving licenses and similar sheet and/or
card and/or book-like documents by means of thermal transfer press
lamination.
[0002] The present invention enables the economical production of
an individual three-dimensional embossing plate for the production
of surface-embossed documents by means of lamination and/or
embossing and/or item-by-item embossing in a hot-cold-lamination
press.
DESCRIPTION OF THE STATE OF THE ARTS
[0003] EP 0 216 947 B1 (Maurer Electronics) and EP 0 219 012 B1
(GAO) and the descriptions of EP 0 842 791 B1 (Giesecke &
Devrient), EP 0 790 898 B1 (Giesecke & Devrient), and EP 0 843
281 A2 (Giesecke & Devrient) describe data carriers with an
optical characteristic of genuineness and processes to produce and
check the data carrier on the basis of lenticular raster elements.
Information is input here by a laser beam to generate a hologram
that will present different visual information at two different
angles of view.
[0004] The known production methods use classical transfer
lamination with multiple repeats and subsequent surface embossing
into a finished document by various methods.
[0005] The documentations for DE 102 01 032 A1, Braun Eckhard
(Giesecke & Devrient GmbH, 81677 Munchen, Germany; "Steel
Engraving Printing for the Production of a Security Document as
well as Steel Plates and Intermediate Products for the Same and
Methods of their Production."), WO 97/19816 A1 (Scheppers
Druckformtechnik GmbH; Saueressig GmbH & Co.), WO 00/00921 A1
(Mazumder), WO 03/103962 A1 (KBA-Giori S.A.), EP 0 322 301 B1
(Banque de France) and WO 03/057494 A1 (Giesecke & Devrient
GmbH) describe methods, processes and equipment for the production
of printing plates, specifically steel engraving plates, for use in
the printing of security documents, specifically of currency
notes.
[0006] All of these processes and machines specify printing plates
or plates for printing applications; however, there is no mention
of a solution for use in a hot-cold-laminating press. GB 401 579
publishes an improved embossing plate made of aluminum or an
aluminum alloy, such as engraving plates, consisting of a hard,
wear-resistant, and attached oxide film or that has a surface
consisting essentially of aluminum oxides. This invention has the
disadvantage that the printing plate is claimed merely as
equipment, but not its use or application.
[0007] U.S. Pat. No. 5,106,125 A publishes a system to improve the
protection against forgery of a security document, where a foil is
attached locally to the surface of the security document, where the
foil has at least one security characteristic, where the security
characteristic has a microstructure for refracting light incidence
and a security profile in the form of a macro structure embossed
into the surface of the security document, where the security
characteristic and the security profile are partially superimposed
such that the relief lines of the macro structure of the security
profile bulge above the plane of the surface of the security
document and exhibit sufficiently recognizable shimmer effects of
light incidence, where the use of this arrangement creates one or
more predetermined breaks in the security characteristic, if the
security characteristic is removed from the security document and
is deformed in such a way that the deformation is easily seen, if
the security document is applied to a second security document.
This invention has the disadvantage that the security profile is
embossed into the surface of the security document.
[0008] There is need of the use of a highly polished embossed
surface and the production of three-dimensional depressions and the
production of raised microstructures and this without damage to the
polished surface. The recessed structures generated in the
embossing plate will be raised in the laminated or surface-embossed
document and the structures raised in the embossing plate will be
recessed in the laminated or surface-embossed document.
THE OBJECTIVE OF THE INVENTION
[0009] The present invention has the objective of economical
production of a structured embossing plate for use in a lamination
press for the production of laminated cards or identity cards, for
example, and similar documents.
THE SOLUTION OF THE OBJECTIVE
[0010] The invention solves the stated objective by the technical
approach of Claim 1 and the other independent claims.
[0011] The problem in the solution of the objective of the
invention was to incorporate three-dimensional structures into a
highly polished embossing plate without damaging the highly
polished surface. The reference surface is defined here as a highly
polished surface that may not be damaged in any case by the
structures described below.
[0012] The invention proposes an embossing plate for a
hot-cold-laminating press with a three-dimensional structure on a
largely flawless metal plate with a hard surface of suitable
thickness and dimensions and with a suitable surface, specifically
a highly polished surface.
[0013] The first embodiment of the invention assumes that the
recessed structure (which preferably has an optical effect) is
incorporated in a single step into the embossing plate as a
three-dimensional structure. The methods to generate such a
structure are described in detail in the following. Each of the
methods described there is intended to be suitable to generate the
desired three-dimensional recessed structure by itself or in
combination.
[0014] However, the invention is not restricted to the production
of the three-dimensional recessed structure in a single processing
step. The following discussion also presents processes with two and
more steps.
[0015] If the three-dimensional structure produced in the first
processing step is to be processed further, a second processing
step is added that realizes the desired additional structuring of
the previously produced three-dimensional structure.
[0016] Likewise, a two-step process is used, if the recessed
structures of the first processing step are applied to an enlarged
processing area, where untouched areas remain within this enlarged
processing area (such as the margins), where the second processing
step adds a different recessed or raised structure (such as
micro-type) to the untouched areas.
[0017] However, the production of recessed and raised structures
requires at least two processing steps.
[0018] This structure is incorporated into the highly polished
surface of the embossing plate by a process with at least two
steps.
[0019] The phrase "process with at least two steps" means that the
structure is incorporated with at least two different processing
steps. It remains an open question whether these two processing
steps are sequential or concurrent. Of course, it is also possible
to use more than two processing steps.
[0020] For example, the first processing step applies a full
coverage of a photo mask by means of lamination, spray, printing,
roller application, flood application and other application methods
and uses a suitable exposure by way of mask exposure and/or laser
exposure.
[0021] Then those structures are uncovered (stripped) that are to
be processed by a subsequent chemical and/or galvanic ablative
process. This method produces three-dimensional recessed
structures.
[0022] Depending on the nature of the chemical or galvanic bath,
the undercut of the masked structures can be controlled to generate
essentially half-round recessed structures, which will generate
lens-like raised structures in use as an embossing plate.
[0023] The second processing step applies a second photo mask on
the entire surface, with particular care that the previously
produced three-dimensional depressions are covered completely.
After a second exposure and uncovering of the second or subsequent
structure to create a raised microstructure on the embossing plate,
a second chemical or galvanic process is used to produce a raised
microstructure.
[0024] As an alternative to this second photo masking and galvanic
process, an additive laser treatment process may be used to produce
the raised structure or a subtracting or ablative laser process may
be used to produce the recessed structure.
[0025] Another embodiment of the invention may use a galvanic plate
in lieu of a metal plate with a highly polished or matt surface.
This variation produces a structure for multiple repeats once and
uses it to produce the galvanic plates. These galvanic plates are
then subjected to further structuring processes.
[0026] The advantage of this variation is that, for example, the
critical lens-shaped structures may be incorporated already in the
first step and that the number of galvanic plate required for the
production run can be produced and that these galvanic plates then
will require only require only relatively simple micro-structuring
processes, but will not require the extensive lens structuring
processes. An additional advantage of this variation is that it
makes high-quality embossing plates available for subsequent
micro-structuring processes.
[0027] The embossing plate produced in this manner will be used to
produce documents, specifically security documents, such as
personal identity cards, passports, identification cards, credit
cards, customer cards, driving licenses and similar sheet and/or
card and/or book-like documents by means of lamination and/or
embossing and/or item-by-item embossing in a hot-cold-lamination
press.
[0028] This normally uses transfer press systems. In this process,
several printed and non-printed sheets that are positioned to match
each other (overlay sheets and core sheets) are laminated to each
other or are connected to each other in a hot press at typically
200 to 300 N/cm.sup.2 and the required lamination temperature of
more than 100.degree. C. to roughly 200.degree. C. and subsequently
in a cold press at typically 200 to 550 N/cm.sup.2 and a cooling
temperature of normally less than 50.degree. C., however preferably
less than 25.degree. C.
[0029] The normal transfer press system usually uses several levels
with cassettes, and several plates and laminating packets are
stacked in the cassettes. Equalizers of fiberglass-reinforced
rubber mats or paper or felt-like spacers are often used between
the cassettes or the plates. These deformable spacers are intended
to increase or improve the uniform area pressure or to equalize
irregularities.
[0030] Normally specialized stainless steel plates with a highly
polished or satin or matt structure are used as printing plates in
a multiple-level press known from the state of the arts. Normally,
these printing plates may be used on both sides. In addition to the
multiple-level press, round-table presses or single press units are
often used.
[0031] Plates with thicknesses between 0.3 and 2.0 mm are used,
preferably with thicknesses between 0.8 mm and 1.5 mm. The format
to be used will be chosen from single use to multiple repeats of
typically 20 or 24 or 48 repeats for laminate elements of credit
card size. A typical plate is produced, for example, by Bohler
Bleche GmbH in A-8680 Murzzuschlag/Austria with the type
designation A-505 in steel quality level DIN 1.4301 or AISI
302.
[0032] Plates with lens structure, usually in the form of raised or
recessed lenticular lens systems, are used to produce documents
with surface lens structure elements. This may use galvanically
produced plates of galvanotype nickel or steel or nickel plates
with lens inserts. Care must be taken in all cases to use plate
pairs with similar coefficients of thermal expansion.
[0033] A plate is defined as a metallic plate with a thickness
between 0.3 and 2.0 mm, preferably with thicknesses between 0.8 mm
and 1.5 mm. The usual format to be used will be chosen from single
use to multiple repeats of typically 20 or 24 or 48 repeats for
laminate elements of credit card size. A typical plate is produced,
for example, by Bohler Bleche GmbH in A-8680 Murzzuschlag/Austria
with the type designation A-505 in steel quality level DIN 1.4301
or AISI 302. Alternatively, galvanically clad steel plates or
galvanically constructed plates, such as nickel plates, may be
used.
[0034] Only plate pairs of the closest comparable coefficient of
thermal expansion must be used in all cases. A high degree of
surface hardness is an advantage for long idle periods. The surface
is preferably highly polished. Satin or matt surfaces may be used
for specific applications. Double-sided plates are normally used in
a level press with cassettes, where the first and last plate is
used with only a single side towards the laminate packet.
[0035] If structured plates or embossing plates are used, the
possibility of double-sided use is also of advantage, but it
encounters technical and economic limits. This requires an
comparison of the required production run or planned series and the
required delivery deadline against the added costs in the
production of double-sided structured embossing plates.
[0036] A document is defined in particular as security documents,
such as personal identity cards, passports, identification cards,
credit cards, customer cards, driving licenses and similar sheet
and/or card and/or book-like documents. Here at least the top
laminate item must be thermoplastically deformable under the normal
surface press power up to 500 N/cm.sup.2 and often at higher power
levels up to about 650 N/m.sup.2. A vacuum-assisted lamination
press may be advantageous for critical embossing. It would
absolutely preclude air pockets.
[0037] A lens structure is defined as a three-dimensional and
optically largely transparent body that is present or is produced
in or on the surface of the document raised and/or recessed by
means of embossing plates.
[0038] The normal embodiment uses lenticular lens systems, where
lens series with varying radius and varying raster dimensions may
be used. This results from the varying embossing height or
embossing depth over the embossed area.
[0039] A simplified embodiment uses lens-like pockets in the
embossing plate, which generate raised lens-like structures on the
document.
[0040] Another embodiment generates first a raised area on the
embossing plate, into which the lens-like structure is
incorporated, and then uses it to produce a document, where the
lens-like structure is situated below the (preferably highly
polished) surface.
[0041] Apart from linear lens-like structures, hexagonal or
triangular or dotted lens-like structures may be used just as well.
The nature of the lens is often not critical, depending on the use,
and relatively large deviations from a radius may be accepted or
desirable. The three-dimensional optical structures may also be
rectangular, parabolic, elliptical, trapeze-like, V-shaped or
irregularly shaped and/or in a composite shape.
[0042] Such three-dimensional optical structures are intended to so
influence the light rays for visual and/or machine viewing of
information contained within, i.e. in the interior of the document,
that there is a change in the visual or machine viewing perception
of this information. As the viewing angle changes, so changes the
selected information.
[0043] If positively bent optical structures are used, there is
also an optical enlargement of an element of the underlying
information, whereas the optical view in level optical structures
depends on the angle relationships.
[0044] Undercut is defined as the production of a photo mask, where
the openings are so small that there is an essentially isotropic
etching, given an appropriate etching bath, thus creating a strong
undercut. This may achieve the same lateral etching effect as in
the vertical dimension, thus generating the desired lens-like
depressions. The prerequisite for such an etching process is a
suitable photo masking, suitable etching bath and flawless plates
or flawless surfaces. Such an etching suffices as a single
processing step to generate a three-dimensional structure recessed
under the reference level in the material of the embossing
plate.
[0045] Microprint is defined as a structure that cannot be read
with the naked eye. The letters may be raised or recessed and may
otherwise be linear or dotted.
[0046] A diffractive structure is defined as a light-bending
optical area or line-shaped or graphically designed element that is
embossed in the surface by the embossing plate. In a preferable
embodiment, the diffractive element is slightly recessed and is
thus protected from mechanical damage, such as scratches and
rubbing.
[0047] Lamination is defined, for example, as treatment in a
transfer press system, a round table press, a feed-through press or
a single packet lamination unit. In this process, several printed
and non-printed sheets (overlay sheets and core sheets) that are
positioned to match each other are laminated to each other or are
connected to each other in a hot press at typically 200 to 300
N/cm.sup.2 and the required lamination temperature of more than
100.degree. C. to roughly 200.degree. C. and subsequently in a cold
press at typically 200 to 550-N/cm.sup.2 and a cooling temperature
of normally less than 50.degree. C., however preferably less than
25.degree. C.
[0048] However, it is also feasible that individual lamination
packets can be laminated in subsequent heat press and cold press
processes, and the lamination process may also be done in a
lamination press, where the heating process and the cooling process
are done sequentially in the same press. Small laboratory units or
experimental units often use this approach.
[0049] A vacuum-assisted lamination press may be advantageous in a
specialized variation of lamination, where it would absolutely
preclude air pockets for uneven layers to be laminated.
[0050] Surface embossing and/or individual surface embossing is
defined as the addition of a surface structure to essentially
completed document. Given that there is at least one thermoplastic
top layer, the embossing plate must be pressed onto the document
surface with a suitable press, while appropriately heated, and the
embossing plate must then be cooled under pressure. This process
requires relatively long processing periods. Ultrasound treatment
and/or microwaves may often yield sufficiently good embossing
results with substantially shorter processing times.
[0051] Some examples of the invention are described in more detail
in the following by reference to figures.
[0052] They show:
[0053] FIG. 1: a schematic drawing of a cross section of embossing
plate (I) with a recessed lens structure (3), raised structures 1
and 2 (4, 5) and a diffractive structure (35),
[0054] FIG. 2: a schematic drawing of a cross section of embossing
plate (1) with a recessed grooved structure (13), a V-shaped
depression (15), with raised structures 1 and 2 in a depression
(16), with raised structures (4, 5, 17),
[0055] FIG. 3: a schematic drawing of a cross section of embossing
plate (1) with photo masking (18) to produce lens-like undercuts
(19, 20, 21),
[0056] FIG. 4: a schematic drawing of a cross section of embossing
plate (1) with a second photo masking (23) to produce a second
surface structure (24),
[0057] FIG. 5: a schematic drawing of a cross section of embossing
plate (1) with a photo masking (18) to produce a surface structure
(25),
[0058] FIG. 6: a schematic drawing of a cross section of embossing
plate (1) with a photo masking (18) to produce a galvanic plate
(26),
[0059] FIG. 7: a schematic drawing of a cross section of embossing
plate (1) with a second photo masking (23) to produce a recessed
lens structure with an undercut (27),
[0060] FIG. 8: a schematic drawing of a cross section of embossing
plate (1) with a recessed lens structure with an undercut (27),
[0061] FIG. 9: a schematic drawing of a cross section of embossing
plate (1) with a galvanic plate (26) and a superimposed diffractive
structure (35),
[0062] FIG. 10: a representative depiction of a document (28) with
lettering (29, 34), a lens raster element (30, 32), a diffractive
element (35) and micro print (31, 33),
[0063] FIG. 11: a schematic depiction of a cross section of the
document example (28) with recessed structures (29, 31, 35) and
raised structures (30),
[0064] FIG. 12: a schematic depiction of a cross section of the
document example (28) with recessed structures (29, 31, 35,
30),
[0065] FIG. 13: a schematic depiction of a cross section of the
document example (28) with recessed structures (32, 35) and raised
structures (33, 34).
[0066] FIG. 1 presents a schematic drawing of a cross section of
embossing plate (1) with a recessed lens structure (3), raised
structures 1 and 2 (4, 5) and a diffractive structure (35).
[0067] Embossing plate (2) may consist here of steel, preferably
stainless steel, and must have an essentially flawless and
non-pitted surface. However, it is also feasible to use a less
rust-resistant steel with a galvanic surface layer, such as nickel.
Or a sheet produced by galvanic means, such as from nickel, may be
used.
[0068] Normally such layers or sheets produced by such galvanic
means have a good flawless material composition, which enables the
incorporation of smallest and three-dimensional structures (3, 7,
8, 9) and also a good adherence with elements (4, 5) applied by
chemical or galvanic means.
[0069] This figure depicts an example of an embossing plate (1)
with a recessed and lens-like structure (3, 7, 8, 9), where this
recessed structure (3, 7, 8, 9) generates a raised and protruding
structure (30, 32)--see FIGS. 10 to 13--on the upper surface of
document (26).
[0070] The normal radius (8) is specified as 70 to 150 .mu.m,
specifically in the vicinity of 90 .mu.m, with a typical depth (9)
of 50 to 120 .mu.m, specifically in the vicinity of 70 .mu.m, and a
raster size (7) of 100 to 300 .mu.m, specifically 170 .mu.m.
[0071] The incorporation of such lens raster elements (3) generates
holograms of printed elements in the interior of document (28).
[0072] The raised structures (4, 5) are additive structures on the
surface of embossing plate (2) and are shown in examples with two
differing heights. Width and height (10, 11) are selectable in wide
ranges. Structures (4, 5) may be embodied here as points, lines or
areas.
[0073] The production of these recessed and raised structures on
both sides of the (highly polished) reference surface (6) is
normally done by a two-step structuring process.
[0074] The first step of the structuring process is a photo masking
of the embossing plate surface (6). A subsequent exposure step with
a mask or a direct exposure system follows. The photo mask is then
removed from the exposed or unexposed areas with appropriate
stripping fluids, depending on the type of the photo mask.
[0075] An appropriate etching control then uses an etching solution
to generate a semi-circular (3) or grooved (13) or V-shaped (15) or
U-shaped recess in the uncovered structures. It is normally
feasible also to recess a larger area (22) without an undercut.
[0076] However, the first step of the structuring process may also
be handled by galvanic action, and either recessed or raised
structures are generated above or below the level of reference
surface (6). Such galvanic action is usually done on a nickel base,
and in the present case the thickness of the galvanic layer for use
in an embossing plate must be produced in a hot-cold-laminating
press.
[0077] The second step of the structuring process may now be
handled by photochemical or photo-galvanic and/or laser action.
[0078] Here the structured surface resulting from the first
structuring process is covered by a photo mask, exposed, developed
and stripped, thus generating a second structure or additional
structures by etching and/or galvanic action.
[0079] The difficulty here is that the structures resulting from
the first structuring process must be covered well, or protected,
which may be done by lamination with a photosensitive film. Such
lamination is usually handled by vacuum lamination and/or by wet
lamination. However, it may also be handled by a flood process or
by spray layering.
[0080] However, at least the second structuring process may also be
handled by a laser process. Recesses may be generated by laser
ablation and raised points by melting of appropriate
surface-applied materials.
[0081] Laser ablation may also produce fine guilloche-like
structures or microstructures. The kind of recess may be controlled
here as steps or as spirals by an appropriate impulse control.
[0082] The laser deposition structure may be accomplished by
application or lamination or spray application or printing
application of suitable materials. The laser beam is led here with
appropriate output and impulse length or impulse frequency and
suitable focus in accordance with the intended graphical design of
the surface. The unused material is then removed.
[0083] The diffractive structure (35) is embodied in this
embodiment variation essentially level with the surface of the
embossing plate (6) and is produced by micro precision etching
and/or by ablative laser action.
[0084] The embossing plate surface (6) in the preferred variation
is highly polished and will not be deformed by the various photo
masking or structural production processes.
[0085] FIG. 2 presents a schematic drawing of a cross section of
embossing plate (1) with a recessed grooved structure (13), a
V-shaped depression (15), with raised structures 1 and 2 in a
depression (16), with raised structures (4, 5, 17).
[0086] In addition to these grooved (13) and V-shaped (15) recesses
with a depth (14) ranging from a few .mu.m to some 50 .mu.m to no
more than 100 .mu.m, many other forms may be designed, where the
photo masking and etching process or the galvanizing process must
be adjusted accordingly.
[0087] The raised structure in recess (16) is generated by a
multi-step process. The cavity must be produced in a first photo
masking process and a first material removal process, and the two
raised structures (16) must be generated in a subsequent additive
process.
[0088] In addition to the creation of raised structures (4, 5),
negative structures may also be generated. To that end, first the
raised area structure is produced and subsequently the recesses
(17) are generated. The resulting structures on document (28) are
naturally recessed (29).
[0089] FIG. 3 shows a schematic drawing of a cross section of
embossing plate (1) with photo masking (18) to produce lens-like
etch patterns (19, 20, 21).
[0090] This FIG. 3 depicts schematically the principle of the
undercut (19, 20, 21), where the semi-circular undercut is only one
example of a possible form. Normally, an isotropic etching speed
may be assumed for an appropriate solution. Thus, the depth of the
lateral etching in the immediate vicinity will be roughly equal to
the general depth.
[0091] Point-shaped or line-shaped lens-like recessed structures
may be produced in this manner.
[0092] In that process, the photo mask (18) plays a very
significant role, since it must remain in place throughout the time
period of the entire chemical or galvanic process and must remain
in good contact with the surface of embossing plate (2).
Subsequently, it must be removable (strippable) without
difficulty.
[0093] The vertical etching without undercut (22) shows that
removal without undercut is feasible for appropriate solutions.
Generally, removal with and without undercut is handled in
different processes.
[0094] FIG. 4 shows a schematic drawing of a cross section of
embossing plate (1) with a second photo masking (23) to produce a
second surface structure (24). This figure will be used to
illustrate the problem of masking for a surface with a previously
produced structure.
[0095] If films are used as photo masks (23) with a photo-polymer
layer thickness of typically 25 .mu.m or 50 .mu.m or 75 .mu.m,
polyester foils are used in addition, which often preclude
lamination of the recessed structures without air pockets. Even
though the state of the arts includes wet lamination foil systems
and vacuum lamination systems, such systems and processes are
cumbersome and expensive. Spraying or squeegee or screen-printing
or flood or roller application are often simpler and more efficient
processes for confirmed lamination. Openings (24) for the second
surface structuring are produced by any process.
[0096] FIG. 5 shows a schematic drawing of a cross section of
embossing plate (I) with a photo masking (18) to produce a surface
structure (25). This step in the production of structure on an
embossing plate (2) serves to uncover an area structure (25) for a
galvanic plate (26).
[0097] FIG. 6 shows a schematic drawing of a cross section of
embossing plate (1) with a photo masking (18) to produce a galvanic
plate (26). This galvanic plate (26) must adhere closely to the
surface of embossing plate (2), must be as flawless as possible,
and should have a similar thermal expansion coefficient as
embossing plate (2).
[0098] Nickel is used as the preferred galvanic material, as it has
a sufficient surface hardness on one hand and a good consistency
for laminating or embossing processes on the other hand.
[0099] FIG. 7 shows a schematic drawing of a cross section of
embossing plate (1) with a second photo masking (23) to produce a
recessed lens structure with an undercut (27). The mask openings
(24) must be aligned precisely with the desired undercut form
(27).
[0100] FIG. 8 shows a schematic drawing of a cross section of
embossing plate (1) with a galvanic plate (26) with recessed lens
structure with an undercut (27). Such a lens structure (27)
facilitates the production of a recessed lens structure (32) on a
document (28).
[0101] FIG. 9 shows a schematic drawing of a cross section of
embossing plate (I) with a galvanic plate (26) and a superimposed
diffractive structure (35). Such a diffractive structure (35)
facilitates the production of a recessed diffractive structure (35)
on a document (28).
[0102] FIG. 10 shows a representative depiction of a document (28)
with lettering (29, 34), where the letters "Austria Card" are added
by means of an embossing plate, which, for example, uses photo
masking with a subsequent chemical or galvanic ablative process to
generate recessed structures or forms a raised microstructure in a
subsequent second processing step after a second exposure and
uncovering with a subsequent chemical or galvanic process.
[0103] The lens raster element (30, 32) shown here likewise has
raised and/or recessed structures, which are produced by the
actions of lens-like recesses in the embossing plate or by a
lens-like structure on a raised area on the embossing plate, where
the lens structures are formed with varying radius and different
raster measurements, which derive from the varying height or depth
of the embossing.
[0104] A diffractive element (35) is included as a light-bending
optical, area or line-shaped or graphical element, which is
preferably situated slightly recessed in order to protect it from
mechanical damage and which has a horizontal, vertical or arch
structure. An element with a diffractive structure may be embodied
in an element with a lens raster structure.
[0105] The depicted micro print element (31, 33) has a structure
that cannot be read with the naked eye and that is likewise raised
and/or recessed, where the structure is in line or point form.
[0106] The raised or recessed structures are normally referenced to
the reference plane (36), which forms the surface of the document
without any added raised or recessed areas.
[0107] Document (28) is normally produced by a transfer press
system known from the state of the arts.
[0108] FIG. 11 shows a schematic depiction of a cross section A-B
of the document example (28) with recessed structures (29, 31, 35)
and raised structures (30). This depiction shows clearly that lens
raster element (30, 32) is embodied as a raised structure and that
micro print (31) is embodied as a recessed structure.
[0109] FIG. 12 shows a schematic depiction of a cross section A-B
of the document example (28) with recessed structures (29, 31, 35,
30), where the specified structures (31, 29, 32) are embodied in
the depicted embodiment of a document (28) as recesses and where
the micro print structure (33) is embodied in addition as a raised
structure.
[0110] FIG. 13 shows a schematic depiction of a cross section A-B
of the document example (28) with recessed structures (32, 35) and
raised structures (33, 34), where the determination of the recessed
or raised structures is partially the reverse of FIGS. 10 to 12 and
where it is determined as a function of the use of document (28),
where the micro print (31, 33) within document (28) may have a
raised or a recessed structure.
REFERENCE IDENTIFICATION LISTING
[0111] 1 Embossing plate (press plate) with three-dimensional
structure [0112] 2 Embossing plate (press plate) [0113] 3 Recessed
lens structure (in the embossing plate) [0114] 4 Raised structure 1
(on the embossing plate) [0115] 5 Raised structure 2 (on the
embossing plate) [0116] 6 Highly polished surface (=reference
surface; optional: satin or matt) [0117] 7 scale of the lens system
[0118] 8 Radius of the lens system [0119] 9 Depth of the lens
system [0120] 10 Height of raised structure 1 [0121] 11 Height of
raised structure 2 [0122] 12 Thickness of the embossing plate
[0123] 13 Recessed structure, grooved [0124] 14 Depth of the groove
or V-shaped groove [0125] 15 V-shaped recess [0126] 16 Raised
structures 1 and 2 in a recess [0127] 17 Recessed structures in a
raised structure [0128] 18 Photo masking (photopolymer mask,
exposed, developed and stripped) [0129] 19 Opening in the etching
mask [0130] 20 Undercut (semi-circular) [0131] 21 Etching depth
[0132] 22 Vertical etching without undercut [0133] 23 Second photo
mask [0134] 24 Second surface structure (chemically ablative and/or
galvanic deposition and/or ablative/deposition by laser) [0135] 25
Surface structure [0136] 26 Galvanic process, [0137] 27 Recessed
lens structure with undercut [0138] 28 Document (ID card) [0139] 29
Lettering (such as Austria Card--recessed or raised) [0140] 30 Lens
raster element, raised [0141] 31 Microprint, recessed [0142] 32
Lens raster element, recessed [0143] 33 Microprint, raised [0144]
34 Lettering, raised [0145] 35 Diffractive structure [0146] 36
Reference level (zero level) document
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